In article ,
The Natural Philosopher writes:
On 02/05/15 14:15, Andrew Gabriel wrote:
In article ,
"Robin" writes:
Davey wrote:
What do they use for those
long-range satellites, like Voyager?

The Voyager satelllites used the heat from radioactiuve decay of
plutonium and thermocouples. It wasn't weapons grade plutonium but if
you tried that at home I think you'd soon make some new acquaintances
early one morning

There's only enough Plutonium-238 left in the world for a handfull
of satellites - US has enough for 3 (bought from Russia, having run
out of its own stock), and Russia probably has around the same amount
itself. This is severely limiting the ability to plan future long
term space missions.

we can always make more if we want to

That might be happening, but I heard it would take until 2021 to make
enough for 1 extra space mission if we started last year.

It also costs much more to make it today than it did to make the
original stock pile that's almost run out, and that's probably more
than most space research programmes are likely to be able to afford.

For radioisotope thermoelectric generators which are not going into
space, there are other options. Strontium-90 has been popular in the
past, but these generators are too big and heavy to send into space.
USSR used lots of them for powering lighthouses, but many have been
lost or stolen after the collapse of the USSR (sometimes killing the
thieves with radiation).

--
Andrew Gabriel
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